Hexbyte Glen Cove When and why did human brains decrease in size 3,000 years ago? Ants may hold clues

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Credit: Pixabay/CC0 Public Domain

The brain is the most complex organ in the human body. Now, a new study has brought us closer to understanding some of its evolution. It shows that human brains decreased in size approximately 3,000 years ago. By studying ants as models to illustrate why brains may increase or decrease in size, the researchers hypothesize that brain shrinkage parallels the expansion of collective intelligence in human societies.

Studying and understanding the causes and consequences of brain helps us understand the nature of humanity. It is well documented that have increased in size over the course of our evolutionary history. Less appreciated is the fact that human brains have decreased in size since the Pleistocene. When exactly these changes happened, or why, was not well known.

“A surprising fact about humans today is that our brains are smaller compared to the brains of our Pleistocene ancestors. Why our brains have reduced in size has been a big mystery for anthropologists,” explained co-author Dr. Jeremy DeSilva, from Dartmouth College.

To disentangle this mystery, a team of researchers from different academic fields set out to study the historical patterns of human brain evolution, comparing their findings with what is known in ant societies to offer broad insights.

“A biological anthropologist and a behavioral ecologist and evolutionary neurobiologist began sharing their thoughts on brain evolution and found bridging research on humans and ants might help identify what is possible in nature,” said co-author Dr. James Traniello, from Boston University.

Their paper, published in Frontiers in Ecology and Evolution, sheds new light on the evolution of our brain.

A recent size decrease

The researchers applied a change-point analysis to a dataset of 985 fossil and modern human crania. They found that human brains increased in size 2.1 million years ago and 1.5 million years ago, during the Pleistocene, but decreased in size around 3,000 years ago (Holocene), which is more recent than previous estimates.

“Most people are aware that humans have unusually large brains—significantly larger than predicted from our body size. In our deep evolutionary history, human brain size dramatically increased,” said Traniello. “The reduction in human brain size 3,000 years ago was unexpected.”

The timing of size increase coincides with what is previously known about the early evolution of Homo and the technical advancements that led to; for example, better diet and nutrition and larger social groups.

As for the decrease in brain size, the interdisciplinary team of researchers propose a new hypothesis, finding clues within ant societies.

What could ants teach us about human brain evolution?

“We propose that ants can provide diverse models to understand why brains may increase or decrease in size due to social life. Understanding why brains increase or decrease is difficult to study using only fossils,” explained Traniello.

Studying computational models and patterns of worker ant brain size, structure, and energy use in some ant clades, such as the Oecophylla weaver ant, Atta leafcutter ants, or the common garden ant Formica, showed that group-level cognition and division of labor may select for adaptive brain size variation. This means that within a social group where knowledge is shared or individuals are specialists at certain tasks, brains may adapt to become more efficient, such as decreasing in size.

“Ant and human societies are very different and have taken different routes in social evolution,” Traniello said. “Nevertheless, also share with humans important aspects of social life such as group decision-making and division of labor, as well as the production of their own food (agriculture). These similarities can broadly inform us of the factors that may influence changes in human brain size.”

Brains use up a lot of energy, and smaller brains use less energy. The externalization of knowledge in , thus needing less energy to store a lot of information as individuals, may have favored a decrease in size.

“We propose that this decrease was due to increased reliance on collective intelligence, the idea that a group of people is smarter than the smartest person in the group, often called the ‘wisdom of the crowds,'” added Traniello.

DeSilva concluded, “We look forward to having our hypothesis tested as additional data become available.”



More information:
Jeremy DeSilva et al, When and Why Did Human Brains Decrease in Size? A New Change-Point Analysis and Insights from Brain Evolution in Ants, Frontiers in Ecology and Evolution (2021). DOI: 10.3389/fevo.2021.742639

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Hexbyte Glen Cove Vermont bald eagle restoration follows years of trying

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In this Aug. 19, 2012 file photo, a pair of nesting bald eagles perch in a tree near their nest on Lake Bomoseen in Castleton, Vt. The state of Vermont is proposing to remove the bald eagle from the state’s list of threatened and endangered species. It comes 13 years after Vermont lost the distinction of being the only state in the continental United States without any breeding pairs of bald eagles. Credit: AP Photo/Toby Talbot, File

Thirteen years after Vermont lost the ignominious distinction of being the only state in the continental United States without any breeding pairs of bald eagles, the state is moving to remove the iconic national symbol from its list of threatened and endangered species.

Since 2008 the number of breeding eagles have grown to where, last year, biologists discovered 64 young eagles in the state and more than 75 were found in a recovery region, which includes portions of New Hampshire and New York.

“They are pretty amazing looking birds. They are huge, first of all, they’re just a striking predator,” said Margaret Fowle, a conservation biologist with Vermont Audubon who has been working on eagle projects in the state for almost 20 years. “For me, every time I see them, it’s kind of awe-inspiring.”

Removing the eagles from the state list was the culmination of decades of work at the state, regional and national level that benefitted a number of other species of birds and other animals, said Mark Scott, the director of wildlife for the Vermont Department of Fish and Wildlife.

“When people care about something and we all come together to work on things great things can happen,” Scott said Thursday.

Habitat destruction and the use of the pesticide DDT beginning in the 1940s reduced the numbers of bald eagles across North America. By the early 1960s, bald eagles—adopted as the national symbol in the 1700s—were nearly wiped out.

DDT was banned in 1972. In 1978, the bald eagle was placed on the federal endangered species list.

Vermont’s list of threatened and endangered species is separate from the federal list, which is managed by the U.S. Fish and Wildlife Service. The bald eagle was removed from the federal list in 2007.

Vermont wasn’t part of the original bald eagle reintroduction plans in the 1970s and 1980s, Fowle said. The eagles were in neighboring states and people expected them to come back to Vermont naturally.

“From what I’ve learned they are sort of slow to pioneer new places so they tend to saturate an area before they spread into new areas,” she said.

Throughout the early 2000s, Vermont biologists were repeatedly frustrated by efforts to bring back the birds, which were known to be successfully breeding in the adjacent states of New Hampshire, Massachusetts and New York. Some were nesting within just a few hundred yards of Vermont.

The state tried to lure breeding eagles to Vermont by building nests and laying deer carcasses near them.

In 2002, eagles were spotted building a nest, but the next year great horned owls took over the nest. In 2005, eagles built two nests in southeastern Vermont but didn’t lay any eggs. Then in 2006, a pair hatched an eaglet in Rockingham—but a few weeks later, the young bird was found dead.

Around the same time biologists began raising young eagles in special boxes in the Dead Creek Wildlife Management Area in Addison. By the time the project ended in 2006, biologists had raised 29 young eagles.

The September 2008 confirmation that a bald eagle pair had successfully raised a young eagle along the upper reaches of the Connecticut River ended Vermont’s distinction as the only state without breeding eagles. It’s unclear if those birds came from the Dead Creek program.

As a proven success to the program, this year the Vermont Endangered Species Committee determined the bald eagle population has grown to the point where it no longer needed the additional protections.

Scott said that even after the eagles are delisted, they will still be protected by state and federal laws.

But it’s not all good news: The Vermont Endangered Species committee is recommending adding the American bumblebee, some species of plants and smaller birds to the state’s list.



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Vermont bald eagle restoration follows years of trying (2021, October 7)
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Hexbyte Glen Cove Ten years of safer skies with Europe's other satnav system thumbnail

Hexbyte Glen Cove Ten years of safer skies with Europe’s other satnav system

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The purpose of the European Geostationary Navigation Overlay Service, EGNOS, is to monitor the real-time performance of US GPS satellites, then generate a correction message, containing information on the reliability and accuracy of their positioning data, which are then broadcast via EGNOS’s geostationary satellites to all suitably equipped satnav receivers. EGNOS consists of three geostationary satellites and a Europe-wide ground segment composed of two master control stations, six uplink stations and a network of 40 monitoring stations, all connected and communicating in real time. Credit: ESA

With 26 satellites in orbit and more than two billion receivers in use, Europe’s Galileo satellite navigation system has made a massive impact. But our continent has another satnav system that has been providing safety-of-life services for ten years now—chances are that you’ve benefited from it without noticing.

Its name is EGNOS, the European Geostationary Navigation Overlay Service. Transmitting signals from a duo of satellite transponders in geostationary orbit, EGNOS gives additional precision to US GPS signals—delivering an average precision of 1.5 metres over European territory, a tenfold improvement over un-augmented signals in the worst-case—and also confirmation of their ‘integrity’ – or reliability—through additional messaging identifying any residual errors.

While its Open Service has been in general operation since 2009, EGNOS began its EU-guaranteed safety-of-life in March 2011.

ESA designed EGNOS as the European equivalent of the US WAAS, Wide Area Augmentation System, working closely with the European air traffic management agency Eurocontrol, passing it to the European GNSS Agency, GSA, to run operationally.

Guiding airliners down

First and foremost its primary customer is aircraft. Imagine an airliner coming into land at Charles de Gaulle, or another major European airport, in bad weather. The pilots cannot see their runway through clouds and rain, but without needing any guidance from the ground they can still confidently descend all the way down to just 60 metres’ altitude before needing to make visual contact with the tarmac—thanks to EGNOS.

France’s Pau Pyrénées Airport was the first airport to utilize EGNOS, on 17 March 2011. Today, more than 385 airports and helipads and 60 airlines across Europe are today utilising such EGNOS-based LPV-200 approaches, short for ‘Localizer Performance with Vertical guidance—200 ft (60 m)’. The freely-available EGNOS service requires no ground equipment whatsoever, replacing the radio guidance beamed upward by traditional CAT I Instrument Landing System (ILS) infrastructure with no decrease in performance.

Cockpit of a new EGNOS-equipped Airbus 350 XWB, on show during the inaugural EGNOS Day at Toulouse-Blagnac Airport on 7 May 2015. Credit: GSA

EGNOS serving drones

Having guided hundreds of thousands of passengers down safely during the past decade—and employed widely in additional sectors such as maritime navigation—EGNOS is now being eyed as the enabler of smaller aerial vehicles making safe use of airspace, in the shape of autonomous drones.

The GSA has supported numerous trials of ‘remotely piloted aircraft systems’ equipped with EGNOS as well as Galileo through its EGNSS4RPAS project. The projection is that crewed aircraft will be vastly outnumbered in our skies by all kinds of automated aerial vehicles, employed for everything from weather and environmental monitoring to personalised delivery services.

The traditional person-based traditional air traffic control model will need to evolve to accommodate such a shift, based on automated monitoring, traffic management and collision avoidance. This highly automated version of air traffic control is termed ‘U-space’.

More than 385 airports and helipads and 60 airlines across Europe are as of March 2021 utilising EGNOS-based LPV-200 approaches, short for ‘Localizer Performance with Vertical guidance – 200 ft (60 m)’. The freely-available EGNOS service requires no ground equipment whatsoever, replacing the radio guidance beamed upward by traditional CAT I Instrument Landing System (ILS) infrastructure with no decrease in performance. Credit: GSA

EGNOS’s safety-of-life service is seen as essential to making this happen, moving from today’s situation where drones are limited to specific air corridors and line-of-sight operations to let them roam freely but safely in busy airspace and built-up areas.

“The whole idea behind EGNOS’s safety-of-life has been to render satellite navigation sufficiently reliable for any kind of use,” explains Didier Flament, leading ESA’s EGNOS team. “After ten years of faultless operations, new applications are becoming plain: drone flight is one example, and EGNOS is also being evaluated for train positioning as well as assisted and autonomous automobile driving.”

New generation of service

ESA retains responsibility for the system’s future evolution, and the middle of this decade should see the debut of its new generation, known as ‘EGNOS v3’.

Didier adds: “While the current system only works with single-frequency GPS signals, EGNOS v3 will operate on a multi-frequency, multi-constellation basis, able to augment all available satellite signals in both L1 and L5 bands, including Galileo. The result will be far enhanced performance and reliability.

“In addition, we are working with developers of other satellite-based augmentation systems around the globe to ensure they stay fully interoperable so for instance EGNOS-equipped aircraft can fly between continents on a seamless basis. Such Interoperability combined with the arrival of the other SBAS systems under development in other regions will lead to a quasi-global worldwide safety of life service coverage in the year 2030.”



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Ten years of safer skies with Europe’s other satnav system (2021, March 17)
retrieved 18 March 2021
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Hexbyte Glen Cove For 50 years, biologist has studied bottlenose dolphins from a research center on Florida's Gulf Coast thumbnail

Hexbyte Glen Cove For 50 years, biologist has studied bottlenose dolphins from a research center on Florida’s Gulf Coast

Hexbyte Glen Cove

Credit: CC0 Public Domain

Beginning his work in marine biology, Randy Wells thought he was a shark guy.

But the teenager whose family had just moved from Peoria to Florida’s Gulf Coast volunteered to help a local researcher study the migration patterns of the bottlenose dolphins off of Sarasota.

And now it’s 50 years later and Wells—a staff scientist at Brookfield Zoo in suburban Chicago since 1989—heads the world’s longest running study of a marine mammal population in the wild, tracking the lives, loves and losses of some 170 Sarasota Bay dolphins and delivering globally significant insight into these creatures that have long fascinated humans.

In the process Wells has become one of the best-known dolphin guys on the planet—and helped make Brookfield more than just a landlocked zoo in a sleepy western suburb.

But the essence of what he has learned, Wells says, is not that different from life in a Chicago ‘burb. He explained:

“So when we started, we had no idea what we were going to find back in 1970. It was completely exploratory, with a pilot tagging study back then, and it could have gone a variety of directions. But the idea that we could find the same identifiable individual dolphins time and time again within a fairly limited area set the stage for everything we’ve been able to do since then.

“So we can recognize 95 percent of the dolphins in Sarasota waters just from looking at their dorsal fin, looking for patterns of nicks and notches on their fins. Within that 170-dolphin community, we have been monitoring them through six generations. At any given time, we can have up to five concurrent generations within a lineage.

“So it’s very much like a suburban neighborhood outside of Chicago. For example, I lived in LaGrange Park for a few years and in the neighborhood that I lived in, there were multiple generations of the same family on back-to-back streets. And that’s kind of how I envision what’s going on in Sarasota.”

That explanation is true enough, but it doesn’t capture the breadth of work that Wells and scores of colleagues and visiting scientists have been able to do over the years from their headquarters on Sarasota Bay.

After first establishing the crucial fact that the wild dolphin population was resident, rather than transitory, Wells and what is now called the Sarasota Dolphin Research Program have helped prove the damage to dolphins and the Gulf of Mexico ecosystem caused by the Deepwater Horizon oil spill, spotlighted the impact of red tide events, pioneered techniques in health assessment of dolphins and established that dolphins can live to age 67 and give birth up to age 48.

“Scotchgard, which we used to put on couches?” said Stuart Strahl, president and CEO of Chicago Zoological Society, the parent organization of Brookfield Zoo. “One of the reasons that’s off the shelves now, it’s a bioaccumulator like DDT.” The original formulation of the 3M product, “that’s off the shelves because of Randy’s research, because of what he found in the dolphins.”

The list of SDRP impacts Brookfield has compiled to mark the 50th anniversary, which happened officially in October, is remarkable for their length and detail, but it would be wrong to think of the program as all white lab coats and clipboards.

“Randy and his crew, they’re the most prolific scientists I’ve ever met,” said Strahl, who has a research background himself. “They are some of the most remarkable humans I’ve seen in the field, and the enthusiasm they have when they see a dolphin they haven’t seen in a while is terrific. ‘That must be so and so!’ It’s infectious when you’re around them.”

And the reason for Brookfeild to continue supporting the program—to the tune of almost $1 million annually, primarily through grants and philanthropy, the zoo says—is because it complements the work done on the zoo campus.

“We have an obligation to engage people in not just the animals that we have on display but also to learn their stories and learn the stories of what things they face in the wild and how those issues can be mitigated,” said Strahl. “It’s two halves of a solution for wildlife.”

Brookfield support is crucial to the project, pointed out Peter Tyack, a professor at University of St Andrews in Scotland who studies cetacean vocalizing and has done research on the Sarasota dolphins.

“Having reliable continuous support is what’s essential for this kind of long-term study,” Tyack said.

And having so much data over so long a time is essential to understanding the big problems of today, including the effects of climate change, Tyack said. “What I say about Randy’s project is … the older the data, the more valuable it gets to us today in terms of tracking long-term trends.”

Another profound impact of the program has been in the development of scientists.

Trevor Spradlin, who is now deputy chief of the marine mammal and sea turtle conservation division at the National Oceanic and Atmospheric Administration, the leading federal marine conservation agency, first experienced scientific field work as a volunteer with Wells in 1989, he recalled.

“Randy has been such a nurturer to so many different generations of marine mammal biologists,” Spradlin said, noting that SDRP’s work is “the blueprint for what we know about coastal dolphins around the world.”

“He’s done so much not just for dolphins but also for the whole field of marine mammal science,” Spradlin said. “He’s provided platforms of opportunity for so many scientists around the world to learn about dolphins and wildlife conservation techniques and procedures.”

More than 80 doctoral dissertations and masters theses have involved work done at SDRP, the zoo says, and just since 1991 more than 400 interns have trained there.

And the work has been a backbone of NOAA’s efforts “to get people to respectfully view animals in the wild,” Spradlin said. “All these efforts to promote safe and reasonable dolphin viewing really have their genesis with Randy. It’s more than just cool science—and it is cool science—but it’s also very important data to help preserve and protect these animals.”

Even growing up in Peoria, Wells was fascinated by water, he said, the result of family spring breaks: “I just—I was taken by the ocean. For years my parents led a delegation that eventually grew to over 500 Peorians that would come down and take over multiple hotels on Panama City Beach.”

The family moved when he was in high school to Siesta Key, just off Sarasota, and “I was so ready for the move,” Wells said. He was able to take classes in high school, and when his dad’s company sold a house to researcher moving from California to study sharks and dolphins, Wells’s father asked the man if he needed an assistant.

Wells began working with that researcher, Blair Irvine (who now sits on the SDRP board), and it was an unfunded offshoot program tagging coastal , Wells said, that led to the pioneering work that established the animals were residents of the area rather than mere passers by.

He has seen remarkable changes in the field. A 1977 marine mammal conference drew fewer than 200 scientists, he said, while one held recently in Barcelona attracted more than 2500. Technology has dramatically aided in the work researchers are able to do, from unobtrusive tracking devices to the dolphin identifying and age-estimating work pioneered by Wells’s team.

But it all comes back to that baseline work his project has done.

“We know the individuals,” he said. “We know how old they are. We know where they are, who they’re related to on the maternal side. And in many cases, with analyses that have just been completed, we know who their fathers are. We have a good sense of their condition in terms of their health and their contaminant load. We know where they spend their time. We know with whom they spend their time. And so with that background knowledge, it just makes all kinds of research possible.

“And it’s just gotten more interesting as time as gone on and we’ve gotten to know these individuals.”

Wells turned 67 in Novembe

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